Final answer:
Sailors in the Mediterranean experience the glow of molten materials at night due to phosphorescence caused by bioluminescent organisms. This natural phenomenon, often described as a bluish gleam or blue flame in the sea, is enhanced in dark conditions free from modern light pollution.
Step-by-step explanation:
The glow of molten materials that sailors in the Mediterranean see at night is often caused by phosphorescence, a natural oceanic phenomenon. Ancient mariners would have been more familiar with dark nights and the resulting visibility of natural luminescence due to the absence of modern lighting that causes light pollution.
Historical accounts and literature describe the sea glowing with a bluish gleam and blue flame, which likely refers to the bioluminescent organisms in the water, such as certain types of plankton that emit light.
When agitated by the movement of the boat or waves, these organisms can create a beautiful, glowing trail in the water, much like the description of a 'gleaming trail of phosphorescence' in historical texts. This enchanting scenario is not unique to the Mediterranean and can be witnessed in various seas around the world where conditions are right.
Such natural occurrences have been the inspiration for sailors' tales and myths throughout history, creating a rich tapestry of maritime culture and contributing to our understanding of the world's oceans.